This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Oxalis stricta L. Sp. Pl. 435. 1753.
Oxalis corniculata var. stricta Sav. in Lam. Encycl. 4:
683. 1797. Xanthoxalis stricta Small, Fl. SE. U. S. 667. 1903.
Plants usually low and erect, pale green. Stem commonly branched at the base, the branches spreading, 5'-6' long, more or less strigose; leaves 9'-1 1/2' broad; leaflets coarsely cellular, very sensitive, closing when touched; petiole-bases narrowly dilated; flowers yellow, fragrant, in umbel-like cymes, peduncles 1 1/2'-6' long, stout; pedicels at length de-flexed; sepals linear or lanceolate, about 2 1/2" long, ciliolate, erect or ascending; petals 4"-5" long, commonly reddish at the base; capsule columnar, 8"-15" long, abruptly narrowed at the summit.
In woods and fields, Nova Scotia to Wyoming, Colorado, south to Florida and Texas. Intrpduced into Europe as a weed. Sheep- or poison-sheep-sorrel. Toad-sorrel. Ladies'-sorrel or -sour-grass. April-Oct.
Oxalis corniculata L. Sp. Pl. 435. 1753.
?0. repens Thunb. Oxal. 16. 1781.
Xanthoxalis corniculata Small, Fl. SE. U. S. 667. 1903.
Plants depressed, green, sparingly pubescent or nearly glabrous, freely branching from the base and with a few branches above. Stem 1'-6' high, the branches loosely pubescent, diffuse, mainly procumbent and often rooting from the nodes; leaflets ob-cordate, wider than long, about i' wide; petioles slender, dilated at the base into oblong rounded or truncate stipules; peduncles 1-3-flowered; flowers yellow, 2"-6" long; pedicels strigillose, more or less reflexed; capsule oblong, gradually narrowed to the apex, 5 '-9" long, appressed pubescent.
In ballast about the eastern sea-ports, and frequently growing on the ground in greenhouses. Texas and throughout tropical America. Has been found in Ontario. Occurs also in warm and tropical regions of the Old World. Ladies'-sorrel. Feb.-Nov.
Oxalis Bushii Small, Bull. Torr. Club 25: 611. 1898. X. Bushii Small, Fl. SE. U. S. 667. 1903.
Plants bright green. .Stems erect, 2'-8' tall, often simple; leaves few; petioles pubescent especially near the base; leaflets with rounded lobes, strigil-lose; peduncles slender, nearly erect, usually solitary, conspicuously overtopping the leaves, glabrous or nearly so except near the base; cymes umbel-like; sepals oblong, 1 3/4"-2" long, obtuse; corolla light yellow, 4i"-6" broad; filaments much dilated at the base; styles slightly pubescent; capsules long-columnar, 6"-7 1/2" long.
In dry soil, Nova Scotia to South Dakota, Colorado and Georgia. May-June.
4. Xanthoxalis r˙fa Small. Red-leaved Wood-sorrel. Fie. 2668.
Oxalis rufa Small, in Britton, Man. 577. 1901. X. rufa Small, Fl. SE. U. S. 668. 1903.
Plants reddish-purple. Stems early branched at the base and decumbent, 4'-12' long, sometimes glaucescent; leaves numerous, commonly clustered; leaflets sometimes pale along the midrib; peduncles glabrous or villous, usually surpassing the leaves; cymes dichotomous or the primary branches suppressed, thus umbel-like or clustered; sepals oblong or oblong-lanceolate, 1"-1 1/2" long; corolla light yellow, 3"-s" broad; petals glabrous, sometimes erose at the apex; capsules short-columnar, abruptly pointed, 4"-6" long.
In woods and moist soil, Massachusetts to Minnesota and Georgia. April-Sept.